Lewis & Short

dĭăpāsōn = διὰ πασῶν (sc. χορδῶν), in music, the whole octave, Vitr. 5, 4, 8; Plaut. 2, 22, 20; Mart. Cap. 9, § 944; so too, dĭăpente = διὰ πέντε, a fifth, Mart. Cap. 9, § 934 al.; dĭătessărōn = διατεσσάρων, a fourth, id. 2, § 107; Vitr. 5, 4, 8; disdĭăpāsōn = δὶς διὰ πασῶν, a double octave, Plin. 2, 22, 20, § 84; Mart. Cap. 2, § 199 al. (All these words should perhaps be written here, as in Macr. Somn. Scip. 2, 1, in Greek letters.)

disdĭăpāsōn, indecl., = δὶς διὰ πασῶν, a double octave in music, Mart. Cap. 9, § 950; Vitr. 5, 4, 9 al.; cf. diapason.